Adiong said almost half of Maute fighters remaining in the battle zone are minors, with around 20 children engaged in actual combat.

"Mga [There are] personal accounts from survivors, from persons, from people that we've rescued," he said. "They have seen as young as 12 years old, carrying high-powered guns and manning the checkpoints."

Joint Task Force Ranao Deputy Commander Romeo Brawner said at the briefing that using child warriors is part of the Maute group's strategy.

Republic Act 10364 or "The Expanded Anti-Trafficking in Persons Act of 2012" prohibits recruiting children for armed conflict.

The country is also a signatory to the United Nations' Optional Protocol on the Involvement of Children in Armed Conflict.

According to the UN protocol, "states will demobilize anyone under 18 conscripted or used in hostilities and will provide physical, psychological recovery services and help their social reintegration. Armed groups distinct from the armed forces of a country should not, under any circumstances, recruit or use in hostilities anyone under 18."

When the children are captured or rescued – the military must turn them over to the Social Welfare department.

A 17-year-old former Maute member told CNN Philippines in July 2017 he was recruited in 2012 in the town of Piagapo in Lanao del Sur when he was 12 years old.

[Translation: They just recruit children and they bring you to their camp. They don't say they're part of Daulah Islamiyah. They say they're from the army. If you want to train for the army, come here.]

"Benjie" said around 40 children, some as young as seven years old, were in the training camp.

He said he was there for two months then he escaped after he found out they were not trained by the military.

Meanwhile, Adiong said government must aggressively educate the youth against extremism.

In response, the Mindanao State University is planning additional subjects to counter radicalism among the youth.

Adiong said this could be a beginning to stem radicalism and extremism among the youth.